Solution routes to metal oxide films through ester elimination reactions

摘要

A method of forming a thin film of a metal oxide on a substrate by coating the substrate with a solution comprising metal-organic precursors is disclosed. This method is applicable to, e.g., forming thin films of perovskite-phase titanates, zirconates, and/or niobates of divalent metals such as Ba, Sr, Pb and/or Ca. In one embodiment, a first precursor comprises a divalent metal coordinated to one or more organic ligands, and a second precursor comprises a tetravalent metal coordinated to one or more organic ligands are supplied in a common solution. A substrate 14 is coated with this solution (e.g. by spin coating) to form a preliminary thin film 10. Substrate heater 22 preferably heats substrate 14 to a temperature sufficient to react ligands from the first and second precursors in an ester elimination reaction which forms a volatile precursor 16. This reaction leaves an intermediate compound film 12 comprising the divalent metal and the tetravalent metal on the substrate. The substrate may be subsequently annealed to drive off unreacted ligands and/or fully crystallize the intermediate compound film into a perovskite-phase film 18.